SO, You Tube kinda sucks. Their videos are never very clear. Have you even tried blowing up a You Tube video to full screen, it SUCKS! It's probably not the best way to view music videos. Many bands are having their videos put out on a separate web page and/or only on Quicktime. The videos are full screen and clear as hell. Here are three that you should watch because they are great looking.
Arcade Fire: Black Mirror
Arcade Fire: Neon Bible
LCD Soundsystem: Sounds of Silver